Any time I try to connect to Gmail, regardless of the URL used to get there, I get the same results that many others have reported: "The page isn't redirecting properly. Firefox has detected that the server is redirecting the request for this address in a way that will never complete."
I've completely cleared my cache and my cookies. All cookies are allowed, including third-parties. I've updated all of my add-ons. I've disabled all of my add-ons. I've used the "Reset Firefox" button to start over completely. Nothing has worked. The only thing that had any effect was creating a new profile for Firefox, using which I was again able to access Gmail. However, that doesn't really solve anything, since I still don't know what's causing the problem and even if I were to go through the huge hassle of moving all of my bookmarks, settings, etc. over to a new profile, it could just as easily happen again.
Does anyone have any idea what could be causing this error?